The revelation – which may mean China has emitted close to a billion additional tonnes of carbon dioxide into the atmosphere each year.

This might also mean those who use China's coal and energy usage as proxies for GDP and GDP growth have underestimated the growth in China.

The new figures add about 600 million tons to China’s coal consumption in 2012 — an amount equivalent to more than 70 percent of the total coal used annually by the United States.

Jan Ivar Korsbakken, a senior researcher at the Center for International Climate and Environmental Research in Oslo, said that based on his preliminary analysis, the new data implied that China had released about 900 million metric tons more carbon dioxide from 2011 to 2013.

China burned or otherwise consumed 4.2 billion metric tons in 2013, according to the new data, and its emissions now far exceed those of any other country, including the United States, the second-largest emitter.

So if China’s emissions have been much greater than believed, researchers will want to understand where the extra carbon dioxide output ended up — for example, how it might have been absorbed in natural “sinks” like forests or oceans, said Josep G. Canadell, executive director of the Global Carbon Project, which studies the sources and flows of greenhouse-gas pollution.